Thujone

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Image:Beta-thujone.png Thujone (C₁₀H₁₆O) is a chemical compound. It is a colourless liquid with a distinctive menthol odour. It is a ketone and a monoterpene, and is found in two stereoisomeric forms: (+)-3-thujone or α-thujone and (-)-3-thujone or β-thujone. Its formal name is sometimes given as bicyclo(3.1.0)hexan-3-one, 4-methyl-1-(1-methylethyl)-,(1S-(1-, 4-, 5-α))-(9CI); other names include isothujone and thujanone. It is used as a flavouring agent in certain foods and is a compound in a number of other food additives. It boils at 201°C and is insoluble in water although it is readily soluble in ethanol or diethyl ether.

1 Sources
2 Pharmacology
3 Regulations
- 3.1 European Union
- 3.2 United States
4 References

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Sources

Thujone is found in a number of plants, such as arborvitae (genus Thuja, whence the derivation of the name), Nootka Cypress, some junipers, mugwort, sage, tansy (25-77% in essential oil) and wormwood, most notably the Artemisia absinthium species, usually as a mix of isomers in a 1:2 ratio.

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Pharmacology

Although it was originally believed to be similar to THC that has since been disproven. Most likely thujone antagonizes inhibition in the gamma-aminobutyric acid (GABA) receptor system.

In mice the LD50 is around 45 mg/kg, 0% mortality rate at 30 mg/kg and 100% at 60 mg/kg. Those exposed to the higher dose had convulsions that led to death in 1 minute. From 30 to 45 mg/kg the mice would experience muscle spasms in the legs which progressed to general convulsions until death or recovery. Pretreatment of diazepam, phenobarbital or 1 g/kg of ethanol protected against a lethal 100 mg/kg dose. <ref>Thujone Gamma-Aminobutyric acid type A receptor modulation and metabolic detoxification. Hold K.,Sirisoma N., Ikeda T., Narahashi T. and Casida J. (2000). Retrieved Nov. 13, 2005.</ref>

There are few studies on humans and the LD50 isn't known. One study in the "journal of alcohol studies" administered 0.28 mg/kg thujone in alcohol, 0.028 mg/kg in alcohol and just alcohol to subjects. The high dose had a negative effect on attention performance. The lower dose showed no noticeable effect. <ref>Absinthe: Attention Performance and Mood under the Influence of Thujone. DETTLING, A., GRASS, H., SCHUFF, A., SKOPP, G., STROHBECK-KUEHNER, P. AND HAFFNER, H.-TH. (2004) Retrieved Nov. 13, 2005.</ref> There is no evidence that any dose will cause hallucinations.

It is best known as a component of the drink absinthe, as it is a component of natural oil of wormwood (Artemisia absinthium). Although it was believed to be the cause of absinthism, an alleged syndrome which caused epileptic fits and hallucinations in chronic absinthe drinkers this has since been questioned. New studies of vintage absinthe, modern absinthe made with vintage recipes and modern absinthe show very little thujone. Most absinthe studied including the vintage were below 10 mg/kg and all were below EU regulations for bitters. <ref>Thujone separating myth from reality. Ian Hutton (2002). Retrieved Nov. 13, 2005.</ref> <ref>http://www.emmert-analytik.de/DLR_100_9_S352-356.pdf Determination of Thujone and Related Terpenes in Absinthe using Solid Phase Extraction and Gas Chromatography] Emmert J., Sartor G., Sporer F., and Gummersbach J. (2004). Retrieved Nov. 13, 2005.</ref>

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Regulations

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European Union

maximum thujone levels in the EU. <ref>Opinion of the Scientific Committee on Food on Thujone Scientific Committee on Food (2003) Retrieved Nov. 13, 2005.</ref>

0.5 mg/kg in food not prepared with sage and non alcoholic beverages.
5 mg/kg in alcoholic beverages with 25% or less ABV
10 mg/kg in alcoholic beverages with more than 25% ABV
25 mg/kg in food prepared with sage.
35 mg/kg in alcohol labeled as bitters.

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United States

Foods or beverages that contain Artemisia species, white cedar, oak moss, tansy or Yarrow must be thujone free.<ref>Food Additives Permitted for Direct Addition to Food for Human Consumption. Food and Drug Administration (2003). Retrieved Nov. 13, 2005.</ref> Other herbs that contain thujone have no restrictions. For example, sage and sage oil (which can be 50%+ thujone) are on the FDA's list of Substances generally recognized as safe. <ref>Substances generally recognized as safe. Food and Drug Administration (2003). Retrieved Nov. 13, 2005.</ref>

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